Siege of Cair Gwent

The Siege of Cair Gwent occurred from 883 to 884 when Wessex laid siege to the Gwentish capital of Cair Gwent (Caerwent) amid the Welsh Rebellion. The siege lasted for a year, and it ended when, in the aftermath of a disastrous Gwentish sortie, the West Saxon besiegers counterattacked and took the city by storm. Afterwards, the West Saxon general Aethelhelm decided to annex Gwent rather than restore its independence.

Background
In 880, the Welsh principality of Gliwissig rose in rebellion against West Saxon overlordship, triggering the Welsh Rebellion. King Alfred the Great was slow to act, as his Wiltshire fyrd under Aelfwald was busy repelling a Nordmann invasion of Hampshire. However, after Aelfwald's victory over the Vikings, he marched back to Wiltshire from Southampton and then crossed the River Severn into South Wales, making landfall in Wessex's other vassal, the Kingdom of Gwent, which had initially taken Wessex's side. However, King Bledri of Gwent was upset that King Alfred had decided to use military force against his fellow Welsh rather than negotiate a peace, and he ultimately decided to declare Gwentish independence as well. Taken aback by Gwent's betrayal, Aelfwald was now forced to besiege the very same kingdom which had previously welcomed him onto its shores. His army laid siege to the Gwentish fortress of Cair Gwent (Caerwent), building siege engines and planning to starve out the numerically-superior Welsh garrison.

In the autumn of 884 AD, Aelfwald was recalled to Winchester and executed for treason after King Alfred discovered that he had secretly been organizing a rebellion against his rule, and King Alfred appointed his nephew Aethelhelm to assume command of the Welsh expedition. A month later, King Bledri attempted to take advantage of the change of command to sortie against the West Saxon army in an attempt to break its siege of the city.

Battle
The main Gwentish army under King Bledri formed the vanguard, while the garrison under Gwriat slowly marched onto the battlefield far behind the main force. Rather than wait for reinforcements, Bledri ordered an attack on the West Saxon army, which was arrayed in a single, long battle line, unlike the multi-tiered Welsh army. Aethelhelm had his army outflank the Gwentish force, encircling King Bledri's army and massacring it from multiple sides; the West Saxon cavalry slaughtered the Gwentish archers before charging into the rear of the Gwentish army. Bledri was killed by West Saxon cavalrymen before he could flee, and much of his force routed. The West Saxon cavalry initiallly pursued the surviving remnants before discovering the Gwentish reinforcements emerging from the trees, upon which the entire West Saxon army reformed its battle line. The second phase of the battle was nearly identical to the first, with the West Saxons launching a second attack on the Gwentmen from all sides and dealing a similar amount of damage. The Gwentish reinforcements were also routed, forcing the Gwentmen to flee to the cover of the city walls.

In the winter of 884, Aethelhelm launched a final assault against the 491 remaining defenders under Ririd and Gwriat, utilizing his army's siege engines and newfound numerical superiority. The West Saxons took the city by storm, suffering 235 losses in the process; only 87 Gwentmen survived to be taken prisoner. Aethelhelm decided not to risk having to face another Gwentish uprising in the future, so he decided to annex Gwent rather than set up a new vassal king. Cuthred was then made Ealdorman of Morgannwg, and Aethelhelm was granted an agricultural estate in Gwent.